Volume 93, Issue 4
September 1984, pages 429-501
pp 429-435 September 1984
Seed morphology of 6 species ofNigella L. (Ranunculaceae) viz.,N. sativa L.,N. hispanica L.,N. arvensis L.,N. orientalis L.,N. nigellastrum (L) Willk. andN. integrifolia Regel, was studied utilising the light and scanning electron microscope to determine the significance of testa features as taxonomic characters. An artificial key based on spermoderm features is proposed to delimit the species studied. The present study supports the treatment ofN. integrifolia Regel as a monotypic genusKomaroffia integrifolia (Regel) Periera.
pp 437-441 September 1984
Development and structure of male and female gametophytes and fertilisation ofCicerbita alpina (Linn.) Wallr. have been studied.
pp 443-448 September 1984
Established populations of crop plant autotetraploids all possess multivalents. However, there is a seeming excess of bivalents in many instances, which is not readily accounted for in theory. To the small number of species, among the auto-tetraploids of which there is quantified information concerning chromosome pairing pattern may now be addedPennisetum typhoides (Burm.) S. & H. (source diploid IP 1475).
pp 449-454 September 1984
Torilis leptophylla, an andromonoecious umbellifer, practises a blend of geitonogamy and outbreeding. Although it exhibits strong dichogamy at the level of individual flowers, in the full plant, pistillate and staminate phases overlap. The ratio of hermaphrodite to staminate flowers is 0·37 which is intermediate to those recorded for other andromonoecious umbellifers.
pp 455-458 September 1984
Antirrhinum orontium, a widely distributed species exists in a number of forms, four of which are studied here. The three European forms are related morphologically and are inter-fertile but the local taxon is not only morphologically different from its European counterparts, but also genetically distinct. It is suggested that the taxon merits a specific status.
pp 459-465 September 1984
A detailed study of surface ornamentation under light and scanning electron microscope is undertaken. The present observations have added further to the knowledge in taxonomic identification ofCosmarium botrytis Menegh, in particular because the species revealed a variety of surface ornamentation based on which various species ofCosmarium are specifically identified.
pp 467-470 September 1984
The structure and development of the ineffective nodules ofTephrosia apollinea, Trigonella polycerata, Vicia hirsuta andV. sativa have been studied and discussed.
pp 471-475 September 1984
Total contents of soluble starch, reducing and non-reducing sugars, soluble proteins and phenols were determined at various stages of development of embryo, endosperm and the endosperm haustoria inCajanus cajan (L.) Millsp. and the results are reported here.
pp 477-484 September 1984
Fertility-induced performance alterations in wheat (cv Kalyansona) have been evaluated under two cycles of droughts at various developmental stages and also repeated droughts. The significant alleviation of growth and yield, despite the higher stress experienced by plants under improved soil fertility, seems to be related to larger root growth and greater post-drought nutrient uptake and not to favourable tissue water modulations. Limited wet-period interludes, under repeated stress, reduced these advantages. Stress-mediated increases in proline and free aminoacids and decline in chlorophyll content in leaves followed established trends. Their levels, however, were relatively higher under better soil fertility. The proline accumulation was reduced in the second cycle of drought, as compared to the first, indicating an absence of hardening effect.
pp 485-494 September 1984
Studies on two species ofMastigolejeunea from Indiaviz M. humilis (Gott) Schiffn andM. repleta (Tayl) St are reported.M. humilis exhibits considerable plasticity in morphology and sexuality as well as intracapsular spore germination. A new variety,M. humilis varciliata var nov is described; it also occurs, in Sri Lanka, Java and Thailand.M. repleta (Tayl) St discovered from Arunachal Pradesh for the first time, is comparatively less variable but shows interesting pattern of disposition of female inflorescences.
pp 495-501 September 1984
Embryology ofTrachelospermum fragrans Hook. f. is described. The anther wall consists of the epidermis, fibrous endothecium, 2–3 middle layers and parietal tapetum. Rarely, endothecium shows 2 layers. The tapetum is uniseriate and remains uninucleate throughout. Simultaneous cytokinesis in pollen mother cells produces tetrahedral and isobilateral tetrads. Degeneration of few pollen grains is recorded. Pollen grain is triporate and 3-celled with few starch grains at anthesis. The ovule is hemianatropous, rarely anatropous, unitegmic and tenuinucellate. The chalazal megaspore of the linear tetrad develops into the 8-nucleate embryo sac of the Polygonum type. Synergids are hooked and the ephemeral antipodals appear egg-like. Fertilization is porogamous. Triple fusion occurs a little earlier than syngamy. The endospermab initio is free nuclear and later becomes cellular. Endosperm haustorium is present. Embryogeny conforms to the Solanad type.